<html>
<head>
	<meta charset="UTF-8">
	<meta content="IE=edge" http-equiv="X-UA-Compatible">
	<meta content="initial-scale=1.0, maximum-scale=1.0, user-scalable=no, width=device-width" name="viewport">
	<title>2805：[Ctsc2012]Circuit</title>
	<!-- css -->
	<link href="../css/base.min.css" rel="stylesheet">
	<link href="../css/project.min.css" rel="stylesheet">
	
	<!-- favicon -->
	<!-- ... -->
</head>
<body class="page-brand">
	<header class="header header-transparent header-waterfall ui-header">
		<ul class="nav nav-list pull-left">
			<li>
				<a data-toggle="menu" href="#menu">
					<span class="icon icon-lg">menu</span>
				</a>
			</li>
		</ul>
		<a class="header-logo header-affix-hide margin-left-no margin-right-no" data-offset-top="213" data-spy="affix">[Ctsc2012]Circuit</a>
		<span class="header-logo header-affix margin-left-no margin-right-no" data-offset-top="213" data-spy="affix">[Ctsc2012]Circuit</span>
	</header>
	<nav aria-hidden="true" class="menu" id="menu" tabindex="-1">
		<div class="menu-scroll">
			<div class="menu-content">
				<a class="menu-logo" href="../index.html">BZOJ离线题库</a>
				<ul class="nav">
					<li>
						<a class="waves-attach" data-toggle="collapse" href="#problems">题目</a>
						<ul class="menu-collapse collapse in" id="problems">
							<li>
								<a class="waves-attach" href="../index.html">主页</a>
							</li>
							<li>
								<a class="waves-attach" href="../list.html">题目列表</a>
							</li>
						</ul>
					</li>
					<li>
						<a class="collapsed waves-attach" data-toggle="collapse" href="#about">关于</a>
						<ul class="menu-collapse collapse" id="about">
							<li>
								<a class="waves-attach" href="../about.html">关于此项目</a>
							</li>
						</ul>
					</li>
					
				</ul>
			</div>
		</div>
	</nav>
	<main class="content">
		<div class="content-header ui-content-header">
			<div class="container">
				<h1 class="content-heading">
                [Ctsc2012]Circuit                </h1>
                <p>时间限制：40s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：128MB</p>			</div>
		</div>
		<div class="container">
			<section class="content-inner margin-top-no">
				<div class="row">
					<div class="col-lg-13 col-md-13">
						<div class="card margin-bottom-no">
							<div class="card-main">
								<div class="card-inner">
									
                                <h3>题目描述</h3><p><p><img alt="" src="../file/2805_0.jpg" /></p>
<p><img alt="" src="../file/2805_1.jpg" /></p></p><hr/><h3>输入格式</h3><p><p class="MsoNormal" align="left" style="margin: 12.75pt -3pt 0pt 42pt; line-height: 13.75pt; text-align: left; mso-line-height-rule: exactly; tab-stops: 95.0pt 141.0pt 264.05pt; mso-layout-grid-align: none"><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">第一行输入N,M分别表示树的节点数和操作<span lang="EN-US"><o:p></o:p></span></span></p>
<p class="MsoNormal" align="left" style="margin: 0cm -1.1pt 0pt 0cm; line-height: 1pt; text-align: left; mso-line-height-rule: exactly; mso-layout-grid-align: none"><span lang="EN-US" style="font-size: 10pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;</span><o:p></o:p></font></span></p>
<p class="MsoNormal" align="left" style="margin: 0cm -3pt 0pt 18pt; line-height: 13.75pt; text-align: left; mso-line-height-rule: exactly; tab-stops: 96.1pt 118.2pt 206.4pt 344.9pt 363.25pt; mso-layout-grid-align: none"><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">个数。接下来</span><font face="Times New Roman"><i style="mso-bidi-font-style: normal"><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><span style="mso-tab-count: 1">&nbsp; </span>N</span></i><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">-1</span></font><span lang="EN-US" style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><span style="mso-tab-count: 1"> </span></span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">行，每行两个数</span><font face="Times New Roman"><i style="mso-bidi-font-style: normal"><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><span style="mso-tab-count: 1"> </span>u</span></i><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">,<i style="mso-bidi-font-style: normal">v</i></span></font><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">，表示有一条连接节点</span><font face="Times New Roman"><i style="mso-bidi-font-style: normal"><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><span style="mso-tab-count: 1"> </span>u</span></i><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">,<i style="mso-bidi-font-style: normal">v</i></span></font><span lang="EN-US" style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><span style="mso-tab-count: 1"> </span></span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">的边，这条边</span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">上恰好包含一个电阻。</span><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><font face="Times New Roman">&nbsp;</font></span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">接下来</span><i style="mso-bidi-font-style: normal"><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><font face="Times New Roman"><span style="mso-tab-count: 1">&nbsp; </span>M</font></span></i><span lang="EN-US" style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><span style="mso-tab-count: 1"> </span></span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">行，每行一个命令，格式见题目描述。</span><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><font face="Times New Roman"> <o:p></o:p></font></span></p></p><hr/><h3>输出格式</h3><p><p class="MsoNormal" align="left" style="margin: 12.75pt -3pt 0pt 42pt; line-height: 13.75pt; text-align: left; mso-line-height-rule: exactly; tab-stops: 107.25pt 219.5pt 231.35pt; mso-layout-grid-align: none"><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">对于每个</span><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><font face="Times New Roman"><span style="mso-tab-count: 1">&nbsp;&nbsp; </span>Q</font></span><span lang="EN-US" style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><span style="mso-tab-count: 1"> </span></span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">命令，输出一个数表示此刻该点的电压</span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">值。你可以输出任意多位的小数，只要你的答案和标准答案相差不超过</span><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><font face="Times New Roman">10-3</font></span><span lang="EN-US" style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><span style="mso-tab-count: 1"> </span></span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">就算</span><span lang="EN-US" style="font-size: 10pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;</span></font></span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">合法。</span><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><font face="Times New Roman"> <o:p></o:p></font></span></p></p><hr/><h3>样例输入</h3><pre>4  3
1  2
2  3
2  4 Q 2 
C 2 4 5  Q 2 
 
 </pre><hr/><h3>样例输出</h3><pre>0.0000000000 -1.6666666666 
</pre><hr/><h3>提示</h3><p><p><img alt="" src="../file/2805_0.jpg" /></p>
<p class="MsoNormal" align="left" style="margin: 0cm -1.5pt 0pt 42pt; text-indent: 0cm; line-height: 13.75pt; text-align: left; mso-line-height-rule: exactly; tab-stops: 227.65pt 289.7pt; mso-layout-grid-align: none; mso-list: l0 level1 lfo1"><span lang="EN-US" style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 宋体; mso-font-kerning: 0pt"><span style="mso-list: Ignore"><span style="font: 7pt &quot;Times New Roman&quot;">&nbsp; </span></span></span><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><font face="Times New Roman">3 &le; <i style="mso-bidi-font-style: normal">N</i>,<i style="mso-bidi-font-style: normal">M</i> &le; 50000</font></span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">，</span><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><font face="Times New Roman"><span style="mso-tab-count: 1">&nbsp;&nbsp;&nbsp;&nbsp; </span>1 &le; <i style="mso-bidi-font-style: normal">u</i>,<i style="mso-bidi-font-style: normal">v</i> &le; <i style="mso-bidi-font-style: normal">n</i></font></span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">，</span><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><font face="Times New Roman"><span style="mso-tab-count: 1">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>1 &le; <i style="mso-bidi-font-style: normal">w</i> &le; 10</font></span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">，树中最长链的长<span lang="EN-US"><o:p></o:p></span></span></p>
<p class="MsoNormal" align="left" style="margin: 0cm -1.1pt 0pt 0cm; line-height: 1pt; text-align: left; mso-line-height-rule: exactly; mso-layout-grid-align: none"><span lang="EN-US" style="font-size: 10pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;</span><o:p></o:p></font></span></p>
<p class="MsoNormal" align="left" style="margin: 0cm -3pt 0pt 18pt; line-height: 14.25pt; text-align: left; mso-line-height-rule: exactly; tab-stops: 71.0pt; mso-layout-grid-align: none"><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">度不超过</span><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><font face="Times New Roman"><span style="mso-tab-count: 1">&nbsp; </span>50</font></span><span style="font-size: 12pt; color: black; font-family: 宋体; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-font-kerning: 0pt">。</span><span lang="EN-US" style="font-size: 12pt; color: black; mso-bidi-font-family: Arial; mso-font-kerning: 0pt"><font face="Times New Roman"> <o:p></o:p></font></span></p>
<p></p></p><hr/><h3>题目来源</h3><p>没有写明来源</p>
								</div>
							</div>
						</div>
					</div>
				</div>
				
				
			</section>
		</div>
	</main>

	<div class="fbtn-container">
		<div class="fbtn-inner">
			<a class="fbtn fbtn-lg fbtn-brand-accent waves-attach waves-circle waves-light waves-effect" data-toggle="dropdown" aria-expanded="true"><span class="fbtn-text fbtn-text-left">Menu</span><span class="fbtn-ori icon">apps</span><span class="fbtn-sub icon">close</span></a>
			<div class="fbtn-dropup">
				<a class="fbtn fbtn-brand waves-attach waves-circle waves-light waves-effect" href="../list.html" target="_self"><span class="fbtn-text fbtn-text-left">题目列表</span><span class="icon">menu</span></a>
				<a class="fbtn fbtn-green waves-attach waves-circle waves-effect" href="../index.html" target="_self"><span class="fbtn-text fbtn-text-left">返回主页</span><span class="icon">home</span></a>
				<a class="fbtn waves-attach waves-circle waves-effect" href="http://www.lydsy.com/JudgeOnline/submitpage.php?id=2805" target="_blank"><span class="fbtn-text fbtn-text-left">提交代码</span><span class="icon">send</span></a>
				<a class="fbtn fbtn-orange waves-attach waves-circle waves-effect" href="http://www.lydsy.com/JudgeOnline/wttl/wttl.php?pid=2805" target="_blank"><span class="fbtn-text fbtn-text-left">试题讨论</span><span class="icon">chat</span></a>
				
			</div>
		</div>
	</div>

	<!-- js -->
	<script src="../js/jquery.min.js"></script>
	<script src="../js/base.min.js"></script>
	<script src="../js/project.min.js"></script>
</body>
</html>